This invention relates to audio speakers, and more particularly, to an improved apparatus for mounting wall or panel mounted speakers which facilitates both the pivoting of the speaker, particularly a tweeter, so that the speaker may be aimed at a listening area and the improved removal of heat from such pivotable speaker.
Speakers which are flush mounted in a wall, panel or other suitable location are becoming increasingly popular in conjunction with various audio and multimedia systems, particularly ones used in homes and offices. However, since aesthetic considerations often dictate the positioning of such speakers, the speakers are frequently forced to operate in locations which are not ideal either from an audio or an environmental standpoint. In particular, such speakers are often expected to be xe2x80x9cinvisiblexe2x80x9d, both as a result of physical shape and physical location at the installation site. As a result, many such speakers are placed near corners, high on a wall, for example near the ceiling, low on the mounting surface, for example near the floor, or at other xe2x80x9cout of sightxe2x80x9d locations. Aesthetic considerations thus result in the loudspeaker rarely being in an ideal acoustical position, with the listener positioned on a substantially perpendicular axis of the speaker; thus requiring that such speakers have uniform, accurate off-axis response in order to maintain superior sound quality. While careful system and cross over design can ensure that most frequencies are reproduced evenly at most off-axis locations, extreme high-frequency content is usually restricted by the geometry of practical high-frequency drive units, and therefore does not radiate evenly in all directions.
One way this problem has been dealt with has been that, rather than insisting on stringent requirements on the uniformity of high frequency radiation in all directions, high frequency speakers (i.e., tweeters) are mounted so that they can be pivoted or aimed, permitting the signal content in the directional band of the tweeter to be properly radiated into the listening area.
However, a problem with existing pivoting tweeters is that the tweeter assembly must be kept small in order to have it fit in a reasonably-sized pivoting mechanism. This generally requires that neodymium magnets or tiny, inefficient ceramic magnets be used to keep the size of the tweeter to a minimum, resulting in a tweeter having little thermal mass and few heat-radiating surfaces. These speakers can therefore handle only modest power without thermal failure. This speaker heating problem is aggravated by the fact that such speakers are frequently mounted in small areas between or behind walls or in other areas with poor air flow for heat removal.
Speaker manufacturers frequently employ high cross-over frequencies in designing these speakers in order to limit the power input to the tweeter; however, this may result in a poor match in dispersion from the woofer to the tweeter. In some cases, a third, mid-high frequency driver must be added to fill in the missing bandwidth, resulting in a much more costly product and a more complex overall system.
A need therefore exists for an improved pivotable speaker mount, particularly for small, high frequency speakers or tweeters, which, in addition to being easily pivotable to permit optimum aiming of the speaker, also facilitates heat removal from the speaker, permitting it to operate at the power levels required for most audio applications without thermal failure.
In accordance with the above, this invention provides a speaker mounting apparatus which facilitates pivoting of the speaker to a desired angular position, while providing increased thermal mass for the speaker assembly, thereby facilitating removal of heat from the speaker. More specifically, the apparatus includes a cup in which at least a drive portion of the speaker is mounted and a mount, the cup and mount being formed and coacting when assembled to each other to facilitate the pivoting of the speaker to a desired angular position and at least the cup providing increased thermal mass for removal of heat from the speaker. The speaker is preferably mounted in the cup so as to facilitate removal of heat from the speaker to the cup and both the cup and mount are preferably formed of materials having good heat transfer properties. A mechanism should also be provided for maintaining good thermal contact between the cup and mount, at least when the speaker is in operation. For preferred embodiments, the thermal contact is between mating surfaces on the cup and mount respectively, the surfaces being shaped to facilitate pivoting of the cup, and thus the speaker, in the mount. A mechanism is preferably provided for normally maintaining the mating surfaces in pressure contact to hold an angular position for the speaker and to facilitate heat transfer from the cup to the mount, while permitting the speaker to be moved to a new angular position. For preferred embodiments, the mechanism permits the pressure contact to be relieved to facilitate pivoting of the speaker to a new angular position.
More specifically, the speaker mounting apparatus includes a cup formed of a material having good heat transfer properties, and having an internal cavity sized to hold at least a drive portion of the speaker, and a substantially uniformly curved outer surface. The mounting apparatus also includes a mount for the speaker, the mount being of a material having good heat transfer properties and having an opening formed therein with a uniformly curved inner surface sized and shaped to mate the curved outer surface of the cup when the speaker is mounted therein; and a mechanism for normally maintaining the mating surfaces in sufficient pressure contact to hold an angular position for the speaker and to facilitate heat transfer from the cup to the mount, while permitting the speaker to be pivoted to a new angular position. Again, the mechanism preferably permits the pressure contact to be relieved to facilitate the pivoting of the speaker. The cup and/or the mount are preferably formed from aluminum or another metal and the curved surfaces are preferably mating partially spherical surfaces. The mechanism for normally maintaining the surfaces in pressure contact may include a spring normally biasing the cup surface against the mating mount surface. For some embodiments, the mount includes a baffle, which baffle may mount a plurality of speakers, at least one of which may be pivotable. A frame of a thermally conductive material may also be provided, the baffle and frame being formed to provide good thermal contact therebetween. The cup may also have fins, with air flowing over the fins at least as a result of convection, to facilitate removal of heat therefrom. Components may also be provided for inhibiting rotation between the cup and mount and/or between the cup and speaker. Mating tabs and slots may, for example, be provided on the mating surfaces of the cup and mount to inhibit rotation therebetween.
For reasons indicated earlier, the speaker is general a high frequency tweeter. For some embodiments, a stem mount is provided which supports such tweeter over a lower frequency speaker. The stem mount is generally of a material having poor heat transfer properties so as to thermally isolate the two speakers and minimize heat transfer therebetween. For this embodiment, the mount for the speaker may have a scalloped square outer surface to enhance audio performance, and in particular to reinforce at the low end of the tweeter frequency response.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings.